Packer assembly for overshots



July 3, 1951 n. w. OSMUN PACKER ASSEMBLY FOR OVERSHOTS Filed Dec. 15, 1948 A WM QTTO/P/VEK Patented July 3, 1 951 UNITED STATES PATENT OFFICE 2,559,315 PACKER ASSEMBLY FOR OVERSHOTS Dean W. smun, Houston, Tex.

Application December 13, 1948, Serial No. 64,935

Claims.

This invention relates to a packer assembly for overshots.

An object of the invention is to provide, in an overshot for pulling stuck pipe from a well, a novel type of packer assembly which will form a fluid tight joint with the upper end of the stuck pipe which is to be pulled.

In operations in a well the pipe, such as a drill stem or other operating string, may become stuck in the well bore so that it cannot be removed as a unit and at times the stuck string of pipe is reversed, or rotated to the left so as to unscrew, or break, a joint above the point at which the pipe is stuck in order that at least a portion of the string may be removed. A coupling is thus left on the upper end of that portion of the string remaining in the well which presents a relative smooth annular upwardly directed face with a relatively smooth inside area adjacent the upper end of the coupling.

In such case an overshot may be lowered into the well over the upper end of the stuck pipe and flushing fluid may then be forced down through the operating string to which the overshot is attached and on down through the stuck pipe and returned up around the outside of the stuck pipe to wash it loose.

In carrying on this operation it is desirable that a seal be provided between the overshot and the upper end of the stuck pipe so as to prevent leakage of this washing fluid between them.

It is one of the prime objects of the present invention to provide an overshot having such seal and which is of such construction that the pressure of the washing fiuid will not only maintain the sealing element in position to break or seal the joint between the overshot and the stuck pipe but will also expand the sealing element so that it will form an eificient seal both above and beneath said joint between the stuck pipe and the overshot.

It is a further object of the invention to provide, in an overshot, a tubular type plunger to which the sealing element is secured and which will effectively apply pressure of the washing fluid to said sealing element to maintain it securely in place.

Other objects and advantages will be apparent ;from the following specification which is illustrated by the accompanying drawings, wherein:

Figure 1 is a vertical, sectional view of the overshot embodying the invention and showing the stuck pipe partly broken away.

Figure 2 is a side elevation of the grapple, and

Figure 3 is a cross-sectional view taken on the line 33 of Figure 1.

Referring more particularly to the drawings the numeral I designates a sleeve like bowl of a general tubular form and whose upper end may be internally threaded for the connection of a coupling 2 thereto to which the operating string 3 is connected. In the present illustration there is shown a tubular guide 4 Whose upper end is shown threaded into the lower end of the bowl and whose lower end is flared internally so as to more readily telescope over the stuck object, as 5, to be pulled.

The bowl is formed with an inside, spiralled downwardly converging seat 6 and above said seat is provided with an undercut spiralled groove i There is a grapple B of spiralled formation, as best illustrated in Figure 2.

The grapple is formed wth an external, downwardly tapering face which is shaped to conform to, and which rides against, the seat 6 and the upper margin of the grapple is formed with an upwardly directed spiralled edge 9. This edge is spaced beneath the groove 1. I

The grapple has the inside spiralled teeth III which are preferably upwardly pitched and which are provided to engage with and grip the object to be pulled.

Located within the lower end of the bowl I above the guide 4 and beneath the spiralled seat 6 there is an annular grapple control designated generally by the numeral H and which is provided with an upstanding key I 2. This key is seated in a longitudinal keyway [3 in the inner side of the bowl, as more clearly shown in Figure 3. The lower end of the grapple 8 has 2. depending finger 8a which fits into the keyway [3 along side the key I2 and which holds the grapple against turning relative to the bowl but which allows a limited longitudinal movement of said grapple relative to the bowl.

In the present illustration the lower end of the coupling 2 is formed into a cylinder [4 and there is a tubular plunger l5 whose upper end works in said cylinder. The upper end of the plunger has an external annular groove l6 in which there is located an O-ring l1 formed of resilient material and which forms a seal with the inner wall of the cylinder around the plunger. The plunger is formed with an external annular, rib l8 therearound which is spaced beneath the lower end of the coupling 2 and spaced beneath said rib and suitably welded withinthe bowl I is a ring I9.

The plunger is thereby retained within the bowl but is allowed a limited longitudinal movement therein.

The lower end of the plunger I5 is internally countersunk as indicated at l5. There is a sleeve-like sealing element 20 formed of rubber or other resilient material whose upper end is fitted into said countersunk portion and secured therein in any suitable manner as by bonding it to the plunger and beneath the plunger the sealing element is outwardly thickened and is shaped to fit within the upper end of the stuck object. This upper end will usually be a pipe coupling such as 2|.

It will be noted from an inspection of Figure 1 that the outwardly thickened portion of the sleeve '20 is formed with an upwardly facing the same and being expansible will take hold of and grip couplings of various outside diameters.

Washing fluid will then be forced down through the operating string 3 and on down through the stuck pipe 5. The pressure of this washing fluid against the upper end of the plunger l5 will force said plunger downwardly and maintain it in contact with the upper end of the stuck object and will also operate radially against the lower end of the sealing element to force it out against the inner side of the coupling 2| so as to form a fluid tight seal between the plunger 15 and the coupling 2|, or other upper end, of the stuck object so that there will be no leakage between them.

Upon upward movement of the tool the seat 6 will move upwardly relative to the grapple 8 thus contracting the grapple into secure engagement with the object gripped thereby and unless too tightly stuck the object will be released and removed from the well.

Should it be desired to release the tool from the stuck object it may be lowered and when the bowl reaches the limit of its downward movement relative to the grapple the spiralled edge 9 will enter the spiralled groove 1 with the result that the grapple is expanded and thereupon, upon rotation of the bowl in an appropriate direction, the grapple will remain in its upper position relative to the bowl and will remain expanded even though the tool may move upwardly as the turning movement takes place. The tool should be rotated in a direction opposite the direction of the pitch and the friction between the bowl and the grapple will maintain the spiralled edge 9 in the spiralled groove 1 and thus maintain the grapple expanded. While the spiralled teeth H! are not in all cases indispensible they are usually provided and if pitched in the same direction as the pitch of the seat 6 they will assist in releasing the grapple. A continuation of this rotation will release the tool from the stuck obj ct and it may be withdrawn.

There has been shown and described what is now considered to be a preferred form of the invention by way of illustration only while the broad principle of the invention will be defined by the appended claims.

What I claim is: p

1. An overshot adapted to telescope over an object to be removed from a well and comprising, a tubular bowl, a grapple in the bowl adapted to engage the stuck object, a cylinder at the upper end of the bowl, a tubular plunger whose upper end is in the cylinder and whose lower end is adapted to land on the upper end of the stuck object, an annular seal carried by the lower end of the plunger whose lower end extends beneath the plunger to fit within the upper end of the stuck object, the upper end of the plunger being exposed to a washing fluid to be forced downwardly through the overshot to hold the plunger in contact with the stuck object and the seal being exposed to said washing fluid to expand 4 the lower end of the seal into sealing contact with the stuck object. 1

2. An overshot adapted to telescope over an object to be removed from a well and comprising, a tubular bowl having an inside seat, a grapple on said seat adapted to engage said object, a cylinder at the upper end of the bowl, a tubular plunger in the cylinder whose upper end is exposed to the pressure of a washing fluid flowing downwardly through the bowl, an annular seal at the lower end of the plunger having an extension adapted to fit within the upper end of the stuck object and expandable radially by the pressure of said washing fluid to form a seal between the plunger and the stuck object.

3. An overshot adapted to telescope over the upper end of a pipe stuck in a well bore and comprising, a, tubular bowl having an inside seat, a grapple on the seat adapted to engage said pipe, a cylinder adjacent the upper end of the bowl, a plunger whose upper end works in said cylinder and is tubular to allow passage of a washing fluid downwardly therethrough, the upper end of the plunger being exposed to the pressure of said fluid to hold the plunger against the upper end of the pipe, a seal carried by the plunger and adapted to be expanded by the pressure of said washing fluid to form a fluid tight seal with the upper end of the pipe when the plunger is in contact with said upper end.

4. An overshot adapted to telescope over the upper end of a pipe stuck in a well bore and comprising, a tubular bowl having an inside seat, a grapple on the seat adapted to engage the upper end of the pipe over which the bowl is telescoped, a cylinder adjacent the upper end of the bowl, a tubular plunger in the cylinder whose upper end is exposed to the pressure of washing fluid downwardly through the overshot, a seal between the plunger and cylinder, the lower end of the plunger being adapted to land on the upper end of the stuck pipe and to be held thereagainst by said pressure, a seal carried by the lower end of the plunger and formed of resilient material adapted to be expanded by the pressure of said washing fluid to form a seal with the upper end of the stuck pipe.

5. An overshot adapted to telescope over the upper end of a pipe stuck in a well bore and comprising, a tubular bowl having an inside seat, a grapple on the seat adapted to engage the upper end of the pipe over which the bowl is 'telescoped, a cylinder adjacent the upper end of the bowl, a tubular plunger in the cylinder whose upper end is exposed to the pressure of washing fluid downwardly through the overshot, a seal between the plunger and cylinder, the lower end of the plunger being adapted to land on the upper end of the stuck pipe and to be held thereagainst by said pressure, a seal carried by the lower end of the plunger and formed of resilient material to form a seal with the upper end of the stuck pipe, said seal extending beneath the plunger and being exposed to the pressure of said fluid to be expanded by such pressure into sealing contact with the upper end of the stuck pipe all the way around- DEAN W. OSMUN.

REFERENCES CITED Name Date Jones et a1 Feb. 25, 1941 Number 

